As a quantity of mobile terminals and a data amount required by a user increase, bandwidth of a frequency band below 6G currently cannot meet a requirement for an increasing communication data amount. Therefore, using a high frequency band (30G to 300G or a higher frequency band) having rich bandwidth resources as a backhaul frequency band and an access frequency band will become a trend. However, compared with a frequency band below 6G a large path loss is one of distinct features of the high frequency band. To ensure a particular transmission distance, a high frequency beam needs to be relatively narrow to achieve a relatively large gain. However, because a coverage area of a narrow beam system is limited, to obtain a maximum antenna gain, a base station (BS for short) end and user equipment (UE for short) need to perform narrow beam scanning and alignment before data transmission, so as to implement normal communication between the BS and the UE.
In a scanning and alignment phase in the prior art, a fixed timeslot used for periodic scanning needs to be configured in each subframe. In addition, traversing needs to be performed in all directions during each scanning, so that an optimal combination of a transmit beam and a receive beam can be selected, to implement subsequent data transmission. For example, a transmit end has four different beams (Z1-Z4), and each beam carries corresponding beam information of the beam. Scanning of the four beams is completed in an initial phase of each subframe, and each beam occupies a timeslot, for example, 10 μs. Therefore, the first 40 μs of each subframe is used for beam scanning and alignment, and remaining 960 μs is used for data transmission. A receive end also has four beams (RX1-RX4), and a scanned beam is changed in each subframe, that is, 1 ms. In this case, a total of 4 ms is required to complete scanning of all 16 beam combinations of the receive beams and the transmit beams. The receive end demodulates beam information of the beams at the transmit end, and then feeds back, in a data transmission phase, information about an optimal combination of a transmit beam and a receive beam to the transmit end (for example, the transmit beam is Z3, and the receive beam is R2). The transmit end performs sending in the data transmission phase by using the beam Z3, and the receive end performs receiving by using the beam R2. Because in the whole process, a fixed timeslot used for scanning needs to be configured in each subframe, and traversing needs to be performed in all directions during each scanning, a lot of time is spent, and a large quantity of resources are occupied.